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From: "Randy Brukardt" <randy@rrsoftware.com>
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Subject: Re: Ada.Text_IO and protected objects (Was: [newbie question] tasks
 and protected types)
Date: Fri, 29 Apr 2005 15:39:26 -0500
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Date: 2005-04-29T15:39:26-05:00
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"Egil H. H�vik" <egil.harald.hoevikNOSPAM@REMOVEkongsberg.com> wrote in
message news:d4tftf$m7i$1@kda-news.kongsberg.com...
>
> "Jacob Sparre Andersen" <sparre@nbi.dk> wrote in message
> news:m2acnhn43i.fsf_-_@hugin.crs4.it...
> > Adrien Plisson wrote:
> > > Jacob Sparre Andersen wrote:
> >
> > > > If calls to Ada.Text_IO _are_ potentially blocking operations,
> > > > that means that one has to move the calls to a task.
> > >
>
> RM 9.5.1(18):
> Certain language-defined subprograms are potentially blocking. In
> particular, the subprograms of the language-defined input-output
> packages that manipulate files (implicitly or explicitly) are potentially
> blocking.

Right. We had a big fight about this rule in the ARG (some people wanting to
repeal or modify it), but ultimately it was left to stand. So it isn't
portable to call Text_IO from a protected object; it might raise
Program_Error or deadlock.

I think it actually does work in Janus/Ada and in GNAT, but (in our case at
least), we aren't making any promises that that will remain the case. And
its always bad practice to write code that will work only on a few
compilers, especially something as hard to track down as this would be.

                       Randy.